significance of maxillary denture bearing area
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  • 1. GOOD MORNING
  • 2. SIGNIFICANCE OF MAXILLARY DENTURE BEARING AREA AND RELATED ANATOMY PRESENTED BY DR NARAYAN SUKLA 1ST YEAR PG DEPART MENT OF PROSTHODONTIA
  • 3. - Introduction - bony structures - mucous membrane - limiting structures - supporting structures - relief areas -conclusion - reference
  • 4. Introduction The anatomical significance and the anatomy of the edentulous ridge in the maxilla and mandible is very important for the design of a complete denture Our objective in fabrication of a complete denture is to provide for a prosthesis that restores lost teeth and associated structures functionally, anatomically and aesthetically as much as possible with preservation of underlying structures and the knowledge landmarks help us in achieving our objective.
  • 5. osseous structures The osseous structures not only support the denture but also have an direct bearing on impression making procedure. Maxillary denture is supported by two pairs of bones, maxillae & palatine bone.  Boucher pg no 148 fig
  • 6. Mucous Membrane Mucous membrane serves as a cushion between the denture base and supporting bone. Mucous membrane is composed of mucosa and sub mucosa. Sub mucosa is formed by connective tissue that varies from dense to loose areolar tissue and varies in thickness. ------compact bon ---------periosteum -------sub mucosa --------mucosa
  • 7. Mucous Membrane Thickness and consistency of the sub mucosa are responsible for the support that the mucous membrane affords a denture, because the sub mucosa makes up the bulk of mucous membrane. In healthy mouth the sub mucosa is firmly attached to the periosteum of bone and will withstand the pressure of dentures. If sub mucosa is thin, soft tissue will be non resilient and mucous membrane will be easily traumatized.
  • 8. According to the clinical significance Landmarks of edentulous jaws Limiting structures Supporting structures Relief areas
  • 9. Limiting structures These are the sites that will guide us in having an optimum extension of the denture so as to engage maximum surface area without encroaching upon the muscle actions Encroaching upon these structures will lead to dislodgement of the denture and/or soreness of the area while failure to cover the areas upto the limiting structure will imply decreased retention stability and support.
  • 10. Labial frenum   It is a fold of mucous membrane at the median line It contain no muscle fiber and has no action of his own CLINICAL SIGNIFICANCE Sufficient allowance should be created in final impression and in complete denture prosthesis  If the frenum is attached close to the creast frenectomy should be done  The labial notch of the denture should be narrow but deep enough to avoid interference  Labichal notch
  • 11. Labial vestibule Labial vestibule (sulcus)-The part of the oral cavity which is bounded on one side by the teeth, gingiva and residual alveolar ridge and on the outer side by lips. It runs from one side of the buccal frenum of one side to the other side ;dividing in two compartments-left and right by the labial frenum  This area is covered by non keratinized epithelium with areolar tissue CLINICAL SIGNIFICANSE  The outer surface of the labial vestibule is the orbicularis oris.* Its fibers run in a horizontal direction; so it has an indirect effect on the denture base  Reflection of the m m superiorly marks the height  The area of reflection has no muscle attachment  Due to this the tissue in this region is movable and lead to over extension  Overextension causes instability/soreness.  •Labial flange
  • 12. Buccal frenum  Single or double folds of mucous membrane.  Broad and fan shaped.  The buccal frenum is the dividing line between the labial & buccal vestibules. It is related to three muscles, so it requires more clearance than the labial frenum  Buccal frenum-Attachment of following muscles;levator anguli oris,orbicularis oris,buccinator. The caninus ( levator anguli oris) attaches beneath and affects its position The orbiculeris oris pulls the frenum forward and buccinators pulls backward CLINICAL SIGNIFICANCE  Moves with muscles of cheek during speech and mastication.  During final impression and in prosthesis clearance should be created for the movement of the frenum overriding will cause pain and dislodgement of denture  During impression the cheeck should Buccal notch
  • 13. Buccal vestibule (sulcus) Extends from anteriorly buccal frenum to the hamular notch posteriorly. Laterally by buccal mucosa, medially by the residual alveolar ridge  The size of the vestibule is dependant upon- contraction of buccinator muscle position of the mandible amount of bone loss CLINICAL SIGNIFICANSE To record maxillary buccal sulcus, the mouth should be half way closed The size & shape of distal end of buccal flange depend up on movement of ramus of mandible at the disital end of the buccal vestibule Hence the patient move the mandible in a lateral protrusive relation so that coronoid process dose not interfere with these function Improper extension causes instability/soreness  Buccal flan
  • 14. The pterygomaxillary (hamular) notch  It is depression situated between the maxillary tuberosity and the hamulus of the pterygoid plate .It is a soft area of loose connective tissue. clinical significance       Used as a boundary of the posterior border of maxillary denture In cases showing gross alveolar resorption the hamular notch disappear, so the back edge of the denture is not carried too far The denture border should extend till hamular notch Aids in achieving posterior palatal seal area Over extension cause soreness Underextention cause poor retention
  • 15. Posterior palatal seal area[post dam]- at or along the junction of the Soft tissue soft and hard palate on which the pressure within the physiological limits of the tissue can be applied by a denture to aid in the retention of the denture Made of two regions·→ 1.Pterygomaxillary seal-The part of the posterior palatal seal that extends across the hamular notch. It extends 3-4 mm anterolaterally to end in the mucogingival junction on the posterior part of the maxillary ridge. 2.Posterior palatal seal-This is a part of the posterior palatal seal area that extends between the two maxillary tuberosity
  • 16. Posterior palatal seal area[post dam]-significance Clinical Reduces the tendency for gag reflex due to downward movement of the denture during incising  .it maintains contact of denture with soft tissue during functional movements of stomatognathic system, by which it decreases gag reflex.  . Decreases food accumulation with adequate tissue compressibility.  Decrease patient discomfort of tongue with posterior part of denture.  Compensation of volumetric shrinkage that occurs during the polymerization  Increases retention and stability by creating partial vacuum.  Increased strength of maxillary denture 
  • 17. Supporting structures Masticatory forces produce quite a pressure on the underlying structures and not everyplace beneath the denture can take such stress hence we need to know the areas which can bear the stresses well. Support is the resistance to the displacement towards the basal tissue or underlying structures. These can be divided into1.Primary stress bearing area 2.Secondary stress bearing area
  • 18. Supporting structures Primary stress bearing area Secondary stress bearing area 1.The horizontal portion of 1. the rugae area the hard palate 2.maxillary tubeorcity lateral to the midline –posterolateral slopes 2.Slopes of residual alveolar ridge
  • 19. Primary stress bearing area These are the areas that are most capable to take the masticatory load providing a proper support to the denture. Some desired properties for primary stress bearing area are1.Tightly adherent sufficient fibrous connective tissue with an overlying keratinized mucosa 2.Presence of cortical bone cover 3.Should be at right angles to the vertical occlusal forces. 4.No underlying structures should be present that will get harmed due to stress
  • 20. Primary stress bearing area Hard Palate - - The anterior region of the hard palate is formed by the palatine selves of maxillary bone The posterior part is formed by horizontal part of palatine bone Covered by keratinized stratified squamous epithelium Anterolaterally, the sub mucosa contains adipose tissue. Poster laterally, it contains glandular tissue. Clinical significance - The horizental portion of the hard palate provides the primary stress-bearing area.
  • 21. Residual alveolar ridge   The portion of the residual bone , soft tissue covering that remains after the removal of teeth . The residual ridge consist of mucosa sub mucosa periosteum and the residual alveolar bone Clinical significance   It is the foundation of denture It is the primary stress bearing area
  • 22. Secondarystressbearingare a rugae area Raised areas of dense connective tissue radiating from the median suture in the anterior 1/3rdof palate It consists of series of ridges in the anterior part of the hard palate Sets at an angle to residual ridge & covered by thin soft tissues Clinical significanse It is considered as a secondary stress bearing area Should not be distorted in the impression.
  • 23. Maxillary Tuberosity   It is the bulbus extension of the residual ridge in the 2nd and 3rd molar region It is the distal aspects of the posterior ridge terminating in the hamular notch Clinical significance    The medial & lateral walls resist the horizontal and torquing forces which would move the denture base in lateral or palatal direction. Therefore, maxillary denture base should cover the tuberosities and fill the hamular notches. Gross enlargement(fibrous or bony – surgical correction. Area of tuberosity
  • 24. Relief area These are the areas which either resorb under constant load or have fragile structures within or are covered by thin mucosa which can be easily traumatized & hence should be relieved.  Incisive papilla  Mid palatine raphae  fovea palatinae
  • 25. Incisive papilla Incisive papilla is a mass of fibrous tissue about 1cm behind the upper incisors.  It is an exit point of nasopalatine nerves and vessels  clinical significance Its position in the edentulous mouth indicates where the incisors and canines should be set.  It should be relieved failure of which would result in necrosis of the distributing areas and paresthesia of anterior palate. burning sensation and pain.  Denture base should be relieved over the area to avoid pressure to the nerves & blood vessels. 
  • 26. Mid palatine raphe  Median suture area covered by thin sub mucosa Extends from incisive papilla to distal end of hard palate.  In the region of medial palatal suture , the sub mucosa is extremely thin ; so relief should be provided to avoid trauma or rocking of the denture  Clinical significance  Relief is to be provided as it is supposed to be the most sensitive part of the palate to pressure  Relieve adequately to avoid trauma from denture base. Median palatine
  • 27. Fovea Palatina    Bilateral indentations near the midline of palate. Posterior to junction of hard and soft palate. These are a pair of mucous gland duct orifices near the midline at the junction of the hard and soft palate. Formed by coalescence of several mucous gland ducts. clinical significance   Aids in determining vibrating line. These landmarks provide a guide to the position of the posterior palatal border of a denture
  • 28. Conclusion Thus, we see that a sound knowledge of the anatomical landmarks of the edentulous jaw is a prerequisite if one has to achieve the objective one has in mind; fabrication of a complete denture that has maximum retention, stability and support with preservation of underlying structures with minimum post insertion problems.
  • 29. References Boucher's Prosthodontics  Essential of complete denture prosthesis by Sheldon Winkler  Clinical dental prosthetics by h r b fenn 
  • 30. Thank u